I'm not 100% sure but haven't Apple made it so you can't use 3rd party things in the dock connector? I'm sure I read that they'd made it so all of the things going into the dock connector have to have a chip inside. I don't know how this works when you use a USB charger and have the cable that came with the iPod? Not sure if they both need a chip?

For what it's worth I've got the official charger and that works well.

I'm not sure, it may well work, I just remembered hearing something about the dock connectors, but with you only having to plug the USB end of the cable into the charger it might not matter which charger it is being plugged into?

It might be worth investigating further on specific electronics forums to see what other people use?